The present invention generally relates to a method and a system for treating a fluid-containing system in order to resist the formation and build-up of scale deposits.
Scale is the build-up of mineral salt deposits on internal surfaces of fluid-containing equipment, such as pipes. In particular, calcium and magnesium, which are commonly contained in water, are heavily involved in the formation of scale.
Scale is formed when mineral ions present in a fluid reach conditions at which they change phases from liquid to solid. Ions present in a fluid require energy to begin the process of forming a solid. Formation of a solid on an existing surface, such as the internal surface of a pipe, requires less energy. Accordingly, it is on the surfaces of pipes and other equipment with which the fluid comes into contact that mineral ions most frequently undergo their phase change to solids. The solids from on, and adhere to, these surfaces, creating scale.
When scale builds up in a pipe or other conduit, it alters the flow of the fluid. By decreasing the volume of fluid that flows through a pipe, scale requires pumps and other industrial equipment to use more energy in order to transport the same volume of fluid. Scale may also increase pressure in a pipe, which can cause leaks and breakages. Because heat provides energy to fuel the ions' phase change to solid, scale build-up on heated equipment, such as steam boilers and heat exchangers, is especially problematic. Scale formation on these devices may lead to reduced heat transmission, higher fuel usage, and even local overheating and failure. The build-up of scale also may have a number of indirect effects, such as providing a location for bacteria to build up in the fluid-containing system and interacting with soap to prevent cleaning of the fluid-containing system.
A number of methods to resist scale formation and build-up are known in the art. For instance, chemical solutions have been introduced into fluid-containing systems. The use of chemical solutions, however, is undesirable both because it requires constant replenishment and because it contaminates the fluid. Accordingly, a number of physical water treatment methods have been identified. One physical water treatment method involves positioning electrodes in the fluid-containing system. However, as the electrodes erode, they lose their effectiveness and need to be replaced. Another method involves the positioning of magnets in direct contact with the fluid. However, the magnets collect magnet debris which, itself, can obstruct the pipe.
Another method of physical water treatment involves the creation of an electromagnetic field, either exteriorly and/or interiorly of a piping system. An electromagnetic signal prevents the formation and build-up of scale by providing energy to the ions, causing them to undergo a phase shift to a solid state within the fluid. Accordingly, the ions stick to each other, rather than to the internal surfaces of pipes and other equipment. As such, they continue to flow through the fluid-containing system and do not build up in the fluid-containing system.
This method of treatment is disclosed, for example, in U.S. Pat. No. 5,514,283. There, an electromagnetic field is created in a fluid-containing system in different ways. One method involves a primary winding of electrical wire, to which an energizing means is connected, and a secondary winding of electrical wire. The primary and secondary windings are separated by a ferrite core. The secondary winding has a pair of terminals, which are placed in electrical contact with a fluid-containing conduit at axially spaced-apart contact zones. A conductive path extends along the conduit between the two contact zones, creating a low voltage, high current signal between the terminals. The high current generates an electromagnetic field that propagates along the conduit in both directions from the contact zones. In another method, a ferrite core is coiled co-axially or spirally around the conduit in a manner so as to extend through a primary winding of electrical wire. In this method, the electromagnetic field is achieved by making the pipe itself and/or the fluid therein serve as the secondary winding.
In many applications of physical water treatment involving an electromagnetic field, it is necessary to have the electromagnetic field freely propagate throughout the fluid-containing system. However, the propagation of an electromagnetic field across large distances in a fluid-containing system has often been difficult and/or impossible to achieve with known methods and devices. For instance, piping configurations in the fluid-containing system create hidden return paths which effectively force the electromagnetic field to a loop, leaving significant portions of the system untreated.